This invention relates to the art of pyroelectric transducers, and more particularly to a new and improved differential pyroelectric detector.
One area of use of the present invention is in infrared radiation detectors, although the principles of the present invention can be variously applied. Differential pyroelectric infrared detectors are employed in intrusion alarm systems, and one problem arising in some prior art detectors is that the active area defining the electrodes will have less infrared absorption than the pyroelectric material which is under and between these electrodes. This will cause the active area to be heated by thermal diffusion when the radiation is not impinged on the active area, thereby giving rise to a false or reduced output indication. Another problem with some prior art detectors arises from optical requirements necessitating very thin electrodes and resultant mechanical difficulties involved in attaching wires to such very thin electrodes.